On the basis of previous work by the principal investigator concerning the synthesis of inhibitors of the enzymatic activities of complement, additional candidate inhibitors are proposed. The proposed compounds are meta- and para-substituted benzamidines. The design of potent specific inhibitors of the enzymatic activities of Cls and Clr is being approached by examining a spectrum of related esterases, thrombin, trypsin, and plasmin and determining the effect of the inhibitors on these enzymes. Multiple-parameter regression analysis will be used to develop methematical models of inhibitor action on the enzymes that are related by their substrate specificities. These models will then be used to direct further synthetic efforts designed to maximize the specificity of the enzyme inhibitory properties of the compounds.